1. Field
The present invention relates to a flexible potentiometer used as a horn actuator in an automobile horn control system.
2. State of the Art
In the 1980's, automobile manufacturers began putting air bags adjacent to steering wheel hubs. FIGS. 1 and 2 show side and front views of a typical air bag system 10. Referring to FIGS. 1 and 2, air bag system 10 includes an airbag 12 between a rigid steering wheel hub 16 and an airbag hub cover 20. Hub 16, which is connected to steering wheel shaft 24, supports steering wheel 26 through supports 32A, 32B, 32C, and 32D.
When the automobile has a sudden impact, a pressure capsule 36 releases a burst of high pressure air into airbag 12. Airbag 12 is inflated in response to the burst. Hub cover 20 splits along a partially perforated line 38 under the force of airbag 12.
Referring to FIG. 3, a typical automobile horn control system 40 includes a horn actuator 42, which may comprise a movable element 44 and a stationary element 46. When the movable element 44 is pressed against the stationary element 46, an electrical path is completed causing an electrical signal to appear on conductor 48 between stationary element 46 and a horn control circuit 52. When the signal appears on conductor 48, horn control circuit 52 activates a horn 56 through a voltage from a power supply 58.
Horn actuators, such as horn actuator 42, have been placed in a variety of positions on the steering wheel and under or on the steering wheel hub cover. However, it has been found safest to position the horn actuators on or under the hub cover so that the driver may activate the horn with the palm of his hand or lower part of the palm of his hand.
Manufacturers of airbag systems have placed membrane switch horn actuators between hub covers and airbags. Various problems, however, have been encountered in providing membrane switches that activate the horn in response to a force within a desired range. Membrane switches have the tendency to require too little or too much force to close.